Always start with the end goals. Whenever you are stuck, refer back to those goals.Our natural human reaction to all this uncertainty is to shift the scope to simplify the problem. Not a bad idea. The issue is that most of us instinctively narrow the scope. After all, that's the intuitive way to simplify.
However, narrowing the scope tends to produce tunnel vision and waste time on local optima. Think of all the times that the discussion of a complex problem goes down a proverbial rat hole as people focus on minutiae.
If you refer back to your end goals instead, you'll keep the team focused on what really matters.